The use case is for an image I made from scratch using gimp, I was thinking about using CC-BY-SA-4.0 but I am not sure if it is the right license for this. The image you print out, cut and then you tape it or glue it to a physical tool that will provide a cheat sheet so you do not have to do the precise math (in mm). It basically goes over the information that is normally there and can give you more precise details than what is already labeled on the tool (working on it still).
Right now there is only one version and each version can give the same level of detail in mm as the tool normally does. I plan on making it so you can have a small mm on a tool labeled for a larger one or maybe a universal one.
The main thing is you can get the exact mm quicker than without it. And it allows you to quickly identify how precise in mm it is without doing the math and you do not need to know how to read the tool to get the information with it.
Basically I want a GPL 2 license but for stuff like this where it is a image cause I believe GPL 2 is more for software and code and not images, documentation.